Field of the Invention
The present invention relates generally to syringes and more specifically to a protective cover for a syringe needle, which reduces the risk of injury due to accidental needle pricks.
Discussion of the Prior Art
In providing medical care for patients, anesthesia is routinely necessary. Anesthesia allows medical professionals to perform complex medical procedures, while the patient is in a sedated state allowing the medical professional more freedom to operate, and minimizing the pain felt by the patient. Anesthesia is usually administered via a non-disposable syringe, through a disposable needle.
The syringes used to administer local anesthetics use a disposable cartridge of local anesthetic and a disposable needle, which attaches to an end of the syringe. The disposable needle is supplied by the manufacturer with a two part protective cover. The back part of the cover fits over the mounting hub of the needle and extends one centimeter past a back end of the front cover and is removed when the syringe is loaded for use. The front portion remains as a protective cover to preserve the sterility of the needle and to protect a user, while handling the syringe prior to and after use. The front portion of the protective cover is referred to as a “needle cap,” because of the manner in which the back portion of the cover telescopes over the front portion and the two are sealed together, an annular ridge or shoulder is created one centimeter from the back end of the front portion of the cap. All commercially available needles for dental office use at this time have a similar ridge or shoulder as the apparatus used to attach the needle to most dental syringes is the same. The needles and their protective needle caps intended for use in dental offices are supplied in different lengths for use in Mandibular and Maxillary injections. The Mandibular needle cap is 4.5 to 5 centimeters long from the previously mentioned shoulder to the front end and the Maxillary needle cap is 3 to 3.5 centimeters long between those points. The diameter of the cap at the shoulder is 1 centimeter and immediately behind the shoulder the diameter is less, usually 0.85 centimeters.
The needle cap is removed immediately prior to administering the injection to the patient. The danger of an infectious needle stick occurs when the protective needle cap is replaced on the needle, post injection, which is now contaminated with the patient's blood and saliva. A single method dominates the dental field and it includes a two handed process. The syringe is normally held in the operator's favored hand and the needle cap is held in the other. The cap and needle are then slowly brought together, until the cap has sufficiently covered the needle and locked into place at the junction of the needle and syringe. If the needle misses the opening in the cap, there is a significant chance that the hand holding the cap will be stuck and the operator exposed to any blood-borne infection carried by the patient.
To avoid this problem, the Center for Disease Control currently recommends discarding disposable syringes without replacing the needle cap. This is impractical in a dental office because only the needle, the covers, and the anesthetic capsule (or cartridge) are disposable; the remainder of the syringe is sterilized and reloaded. Often a needle is used multiple times on a single patient to administer additional anesthetic. Though the risk of an accidental stick is greater handling the uncapped syringe needle than the risk to recap the needle, needles are still reused to save time and money.
There are techniques for handling the recapping procedure to avoid the danger of a stick such as the “scooping” the cap off a table top, commonly called the ‘one-handed scoop method’ with the needle and pressing the cap against a wall to seat the cap on the needle base or holding the cap with a hemostat or forceps instead of the hand. These techniques work, but they are awkward at best, allow for the risk of picking up spatter, which might have fallen onto the dental tray and often ignored out of convenience. Moreover the method name is a misnomer; it in fact does require a second hand to fasten the cap securely to the needle hub once it is in place. While this method is commonly taught in dental schools, it is rarely used by tenured dentists in favor of the two-handed technique.
U.S. Pat. No. 3,605,744 to Dwyer discloses an injection apparatus and method of injection. U.S. Pat. No. 3,820,652 to Thackston discloses a packaged syringe construction. U.S. Pat. No. 5,222,502 to Ku rose discloses a blood collecting needle. U.S. Pat. No. 6,485,469 to Steward et al. discloses a shielded dental safety needle.
Accordingly, there is a clearly felt need in the art for a protective cover for a syringe needle, which reduces the risk of injury due to exposure to blood borne pathogens, because of accidental needle stick injuries incurred, while attempting to recap a syringe needle.